Tension device for sewing-machines.



1.0. HUFFMAN & E. J. LAUFFER.

TENSION DEVICE FOR SEWING MACHINES.

' APPLICATION FILED JAN-30.1913.

I 1,167,823. Patented Jan. 11, 1916.

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JOHN D. HUFFMAN AND EMI-L J; LAUFFER, 0F CLEVELAND,- OI-IIO, ASSIGNORS, BY

MESNE ASSIGNMENTS, TO THE WHITE. SEWING MACHINE COMPANY, OF CLEVE- LAND, OHIO, A CORPORATION OF OHIO.

TENSION DEVICE nos sEtv-mammmss.

Specification of Letters Patent.

Patented Jan. 11 ,1 916.

Application filed. January so, 1913. Serial no. 745,076i

To all whom it may concern Be it known that we, JOHN O. HUFFMAN and EMIL J. LAUFFER, citizens of the United in which the present inventionis embodied,

is constructedwith special reference to at taining certain desirable qualities which are due wholly or partly to said invention. For example, the tension device is a self contained piece of mechanism, the parts of which may be assembled and adjusted, apart from the machine, and then this piece of' mechanism may be secured to the machine head in working relation to the parts thereof. Moreover, this tension device is so constructed as to make 1t easy to quickly put the thread between the tension disks where it belongs, and to practically prevent the thread from going anywhere else and so becoming tangled in any other part of said device. Additionally, the construction is such that the tension on the thread may not" only be increased and diminished, but may with certaintv be restored to a given condition, which, for example, was found to be satisfactory upon a certain piece of work.

In the drawing, Figure 1 is a sectional side elevation of a tension device embodying" the invention, and the adjacent parts of'the sewing machine head to which it is removably secured. Fig. 2 is a side elevation of said tension device.

Referring to the parts by letters. Trepresents a partof the machine head. The front Both of these figures are double size. Fig. 3 1s a rear view of the plate-t is the part to which the tension device is removably secured, so as to project at ltsrear end through ahole 6 S represents the needle bar; Q the presser bar; R- the pres'ser bar lifter; and U the tension release lever. Theabove mentioned parts are old either in the form'shown' or in some equivalent form; The lever U is of" bell crank form,'and' onearm is extended to a point where the'presser loar lifter will operate it at the-sametime that it lifts the presser bar. The tenslon device includes as its main frame'member a thin metal base plate A adapted tio be laid fiatagainst andthen connected' byfscrews 2'with the machine head. A tubular stud B isfixed to saidplate and extends through the same, projecting both in frontofand be'hinditi The projectingrear part of this stud serves to support and anchor thethread' take up springD, by means which will be presently described.

One tension disk O lies against and is fixed to said back plate, and the stud B passes centrally through it. Themovable tension disk (l 'embraces the stud in front of the fixed clisk.' These two disks are substantially dish shaped,-their middle portions being bent away from each other so as to leave a recess between them when their opposed" faces engage. In this recess between th'e'di'sks a thread sheave F is placed, which sheave loosely embracesand is freely rotatable uponthe stud. Outside of the movable tensiondi'sk C is the tension release plate D. This not only embraces the stud, but it has a' bar 62 which passes through and is movable in a longitudinal diametri cal slot b in said stud. Outside of'this plate' and engaging withit is thetension spring E. This is in the form of a thin metal disk which loosely embraces thestud B and has a plurality of rearwardly bent arms 6 which r I Outside of this spring the tension nut Gr screws 'onto engagethe tension release plate.

the threaded front end of stud B and into engagement with the' tension spring so as to apply to it the proper tension which will be transmitted through the tension release plate D to the movable disk C A cup shaped indicator disk H is clamped to this tension nut.v It has a rearwardly projecting annular flange h which extend'srearwardly far enough to make it substantially impossible to get the thread anywhere in the device except between the two tension disks C, C where it belongs. On the front face of this disk H are indicator graduations 0 to 8, inclusive, which are intended to be read in connection with a. pointer J which is fixed to the back plate and extends over the indicator disk. (in this indicator disk are two outwardly projecting lugs h which, by. engaging with this pointer, bring the indicator disk to a standstill. That is to say, they limit the possible turning of the disk to a trifle less than one complete revolution. In order to fasten this indicator disk to the tension nut a finger piece K is utilized. This slips somewhat tightly over the front end of the tension nut; and when sufliciently pushed back will clamp the indicator disk between itself and an annular shoulder g on the nut. A screw is which screws radially thr ugh this finger piece engages the little beveled flange 9 on the tension nut, wherefore when this screw is screwed in the finger piece is pulled rearward so as to clamp the tension disk, as stated. When the parts are assemble and before the indicator disk is clamped to the tension nut, this nut is screwed on until I zero.

the two tension disks are pressed toward each other with the desired minimum tension. Then the indicator disk is placed in such relation to the pointer as to indicate Then this indicator disk is clamped to the tension nut by the finger piece and its screw. Now, when it is desired to apply more tension, the tension nut and disk are turned so as to screw the nut onto the stud B. if, the user of the machine is using it on thin goods and finds that the tension is right for this work, when the indicator disk reads 3, for example, this can be remembered. The tension may then be changed for other work, but when the operator begins to work upon the same class of thin goods, it is easy to restore the tension device to the condition found to be best for that particular use.

, In the tubular stud and projecting rearward therefrom is a tension release pin M, the front end of which engages the cross bar (Z on the tension release plate D. The rear end of this pin M is engaged and moved forward by lever when the latter is operated as before described. By this forward movement of the said pin M the tension re lease plate is moved forward so as to relieve the pressure tending to force the tension disk C toward the fixed disk C.

Associated with all efficient tension devices is a very light thread take up spring. Such a spring N is shown in the drawing as a part of this device. There is a long tubular coil N of fine spring wire which terminates in the hook shaped arm n which is extended into the path of the thread as it passes out from between the tension disks.

This coil of wire embraces a split cylinder P which fits friction tight upon the projecting rear end of the stud B. This split cylinder has two arms 79, 79 one of which engages with a loop on the rear end of the spring coil and anchors it. The other end extends to a. position where it may be conveniently reached by means of a tool such as a screw driver, through a hole in the side of the head. Vith this tool the operator may turn this split cylinder upon the projecting rear end of the stud and so wind up or unwind the spring coil, and thereby apply greater or less tension to the thread take up spring arm.

Having described our claim:

1. In an upper thread tension device for sewing machines, the combination of a fixed stud adapted to be secured to the sewing machine head, and to project forwardly therefrom, said stud being externally threaded at its front end, a fixed tension disk, and a movable tension disk,both of .which embrace said stud and have opposed invention,

iave their marginal edges curved away from each other, a spring acting to press he movable tension disk against the fixed ension disk with greater or less force, a ension nut which screws onto said stud igainst said spring to vary the tension of aid spring, and an annular indicator disk which is centrally fixed to said nut and has a rearwardly extended cylindrical marginal iange,the rear edge of which is extended rearwardly past the plane in which lies the front edge of the movable tension disk.

2 In an upper thread tension device for sewing machines, the combination of a fixed stud adapted to be secured to the sewing machine head and to project forwardly therefrom, said stud being externally threaded at its front end, a fixed tension disk, and a movable tension disk,both of which embrace said stud and have opposed annular surfaces which are in contact and have their marginal edges curved away from each other, a spring acting to press the movable tension disk against the fixed tension disk with greater or less force, a tension nut which screws onto said stud against said spring to vary the tension of said spring, and an annular indicator disk which is centrally fixed to said nut and has a rearwardly extended cylindrical marginal flange,the rear edge of which is ex tended rearwardly past the plane in which lies the front edge of the movable tension disk, and a fixed pointer for cooperation with said indicator disk.

3. In an upper thread tension device for sewing machines, the combination of a fixed stud adapted to be secured to the sewing machine head, and to project forwardly nnular surfaces which are in contact and therefrom, said stud being externally threaded at its front end, a fixed tension disk, and a movable tension disk,both of which embrace said stud and have opposed annular surfaces which are in contact and have their marginal edges curved away from each other a spring acting to press the movable tension disk against the fixed tension disk with greater or less force, a tension nut which screws onto said stud against said spring to vary the tension of said spring, and an annular indicator disk rearwardly past the plane in which lies the front edge of the movable tension disk, a pointer, and two stops carried by said indicator disk for engagement with opposite sides of said pointer to limit the turning movement of said indicator disk.

In testimony whereof, we hereunto afiix our signatures in the presence of two witnesses.

JOHN O. HUFFMAN. EMIL J. LAUFFER.

Witnesses:

E. L. THURsToN, E. B. GILCHRIST.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0." 

